TERCOS: A Novel Technique for Exploiting Redundancies in Fault-Tolerant and Real-Time Distributed Systems

In this paper, we propose a novel fault-tolerant technique, which is seamlessly integrated with fixed-priority-based scheduling algorithm to explore redundancies to enhance schedulability in fault-tolerant and real-time distributed systems. Our fault-tolerant technique makes use of the primary-backup scheme to tolerate permanent hardware failures. Most importantly, the proposed technique (referred to as Tercos) terminates the execution of active backup copies when corresponding primary copies are successfully completed, therefore Tercos can reduce scheduling lengths in fault-free scenario to enhance schedulability by virtue of executing portions of active backup copies in passive forms. Experimental results show that compared with existing algorithm in literature, Tercos can significantly improve schedulability by up to 17.0%(with an average of 9.7%).